1. Field of the Invention
The present invention relates to an object, a method, or a manufacturing method. The present invention relates to a process, a machine, manufacture, or a composition of matter. One embodiment of the present invention particularly relates to a semiconductor device, a light-emitting device, a display device, an electronic device, a lighting device, a driving method thereof, or a manufacturing method thereof. In particular, one embodiment of the present invention relates to a display device (display panel). Another embodiment of the present invention relates to an electronic device, a light-emitting device, or a lighting device which includes a display device, or a manufacturing method thereof.
In this specification and the like, a semiconductor device generally means a device that can function by utilizing semiconductor characteristics. A transistor, a semiconductor circuit, an arithmetic device, a memory device, and the like are each one embodiment of the semiconductor device. A light-emitting device, a display device, a lighting device, and an electronic device may each include a semiconductor device.
2. Description of the Related Art
Display devices such as a liquid crystal display device and an EL display device, which are used for electronic devices or the like, are required to have narrower bezels so as to be reduced in size and designed more freely. In order to narrow the bezel, it is effective to provide a pixel portion and a part or the whole of a driver circuit over the same substrate.
In general, such a driver circuit is formed using a complementary metal oxide semiconductor (CMOS) circuit; however, the driver circuit can also be formed using transistors having the same conductivity type. For example, Patent Document 1 discloses a technique in which a circuit such as a shift register is formed using transistors having the same conductivity type.